Apparatus for treating metal borings



Feb. 23, 1960 w. D, MacDQNALD 2,925,821

APPARATUS FOR TREATING METAL BORINGS Filed Feb. 20, 1956 2 fleets-Sheet1 CLEAN DRY, AND COOLED CUTTINGS Ward D. MacDonald ATTORNEY OILY METALCUTTINGS Feb. 23, 1960 w. D. MacDONALD 2,925,321

APPARATUS FOR TREATING mam. BORINGS Filed Feb. 20, 1956 2 SheetsSheet 2uvmvrm Wa r0! D, Mac Donald A TTORNE Y APPARATUS FOR TREATING METALBORINGS Ward D. MacDonald, North Muskegon, Mich., assignor to MichiganFoundry Supply Company, Muskegon, Mich, a corporation of MichiganApplication February 20, 1956, Serial No. 566,495

11 Claims. (Cl. 13465) This invention relates to apparatus for treatingmetal borings. More particularly, this invention relatesto apparatus forcleaning oily, metallic cuttings for use in making aniline or any othercompound requiring clean iron particles.

Aniline (C H NH is a parent substance for making dies, drugs and otherchemicals. It is made by the reduction of nitrobenzene with iron filingsor borings, generically referred to herein as cuttings, withhydrochloric acid as a catalizer. This reduction process requiresexceedingly clean iron cuttings. The source of such cuttings arefoundries or other machine shops of which cuttings are a by-product fromtheir boring, milling and other operations. In these operations, coolingand lubricating oils are used. This oil adheres to the cuttings,requiring the removal of same before the cuttings can be used in theaniline reduction process. This invention relates to the method andapparatus for cleaning this oil from the cuttings.

The only known method for cleaning such cuttings is to burn oiltherefrom and then cool the cuttings by passing them through a zonesurrounded by a cooling jacket through which water or other coolant iscirculated. This previous type method and apparatus used has beenunsatisfactory for several reasons. First, the oil content of thecuttings produced by. such apparatus has been comparatively high, thusadversely influencing the effectiveness of the iron in the reductionprocess. These prior apparatuses also have a relatively low productionrate of three to five tons per hour. In passing through the cooling zoneat the extreme temperatures of the cuttings, oxidation occurs, whichalso influences the efiectiveness of the iron in the reduction process.Such oxidation also results in great losses of iron particles. Losses ofiron particles, particularly the fines is an unsatisfactory result fromthe high air currents passing through the cooling chambers.

Another disadvantage of previous apparatus is the required low oilcontent of the cuttings which can be handled by such methods. To myknowledge, other apparatus requires less than 1% oil content.Apparently, this is due to the extreme temperatures, fuel and time,required to burn ofl? greater quantities, such temperature elevationrequiring more fuel and more elaborate cooling equipment.

This invention is designed to avoid and eliminate these disadvantages ofprior methods. Therefore, an object of this invention is to provideapparatus for faster cleaning of oily cuttings.

Another object of this invention is to provide apparatus for cleaningoily cuttings in which the resultant product has a low oil content andvery little oxide or corrosion.

Still another object of this invention is to provide apparatus forcleaning oily cuttings in which the loss due to oxidation and loss offines is appreciably reduced.

A further object of this invention is to provide apparatus for cleaningoily cuttings which, under certain connited States Patent ice ditions,will not require any fuel except to start the method, thus making theprocess exothermic.

Other objects of this invention will become obvious upon reading thefollowing specification in conjunction with the accompanying drawingswherein:

Fig. 1 is a block diagram of my method schematically representing thevarious steps.

Fig. 2 is a side elevational view of my apparatus for carrying out themethod.

Fig. 3 is an end view of the burner taken along the plane III-Ill ofFig. 2.

Fig. 4 is an end view of the mixer taken along the plane IV--IV of Fig.2.

Fig. 5 is an end view of the dryer taken along the plane V--V of Fig. 2.

Briefly, this invention is concerned with apparatus for cleaning oily,metallic cuttings. The apparatus performs the steps of burning the oilfrom the cuttings and mixing 1 water with the cuttings after the oil hasbeen burned therefrom. This mixture of water and cuttings is then passedthrough a drying zone, the cuttings being almost entirely cooled by theevaporation of the water. Thus, the heat removed from the cuttings issubstantially equal to the heat of vaporization required by the water.The specific apparatus for performing this method comprises a burnerhaving means for burning the oil from the cuttings as they passtherethrough. A mixer is provided for mixing water with the cuttings.The mixer passes the mixture of water and cuttings to a dryer where thecuttings are dried by evaporation of the water from the cuttings.

The steps performed by the apparatus of this invention as schematicallyillustrated by Fig. 1 comprises three main steps-bufning'of oil from thecuttings; mixing the hot cuttings with a predetermined amount of water;and

then cooling and drying the cuttings by the evaporation of the watertherefrom.

In accordance with a broader aspect of this invention, the oil is burnedfrom the cuttings by any conventional method. It is important thatsubstantially all of the oil be evaporated from the cuttings and burned.To accomplish this purpose, I have found that the operating temperatureof the burner should indicate from 700 to 1200 degrees F. In theconventional method, the burner is fired by fuel such as gas, oil, orother hydrocarbon fuels.

In passing the oily cuttings through the burner, the cuttings themselvesshould normally reaeh a temperature of 800 to 900 degrees F., at whichtemperature substantially all of the oil is evaporated from the cuttingsand burned into waste gases.

Although conventional apparatus for burning the oil from the cuttings isused in a broader aspect of this invention, I havefound that a muchimproved result is obtained by my preferred and novel apparatus whichcauses initial auxiliary firing of the furnace by the addition ofhydrocarbon fuel but eventually causes self-firing by the oil on thecuttings by passing excess oxygen and sufficient cuttings through theburner to provide enough fuel for firing the process. In order toaccomplish this, I draw excess air through the burner supplying it withadditional oxygen for completing the combustion of the oil.

In conventional burners of the size comparable to that of thisinvention, passing more than five tons of oily cuttings through theburner is extremely hazardous due to the large quantities of storedcombustible material accumulating in the burner. These excess quantitiesof combustible materials, in the form of smoke, gases and suspendedliquid hydrocarbons, frequently causeexplosions. I have found that whenexcess oxygen is supplied to the burner this hazard is eliminated. Suchexcess oxygen provides a self-firing, exothermic process rcquiring noadditional fuel except that necessary for initially starting theprocess. The excess oxygen permits passing cuttings of high oil content,and greater quantities of such cuttings through the burner withresultant greater quantities of oil beingburned from the cuttings. Myapparatus will process cuttings with any oil content, the greater thebetter. Older apparatus require cuttings of less than 1% oil. The oilcontent range of the cuttings resulting from my invention is from to0.005%. My apparatus can handle fifteen tons per hour of cuttings ascompared to three to five tons per hour in old methods.

By supplying excess oxygen as used herein, is meant the supplying ofoxygen in quantities greater than that normally occurring in the burner.Therefore, forcing or drawing excess air through the burner suppliesexcess oxygen. Pure oxygen or oxygen in various degrees of concentrationin a particular gas is satisfactory but cost prohibitive. Thisadditional air can be injected or drawn into the burner at the front oftheburnenat several points or any suitable location which proves to besuccessful in causing'more complete combustion of the oil on thecuttings. In my preferred form, the excess air is injected or withdrawnat the inlet end of the burner.

The next step after the oil has been burned from the cuttings is to mixthe cuttings with water. The amount of water mixed with the cuttings isextremely important. The optimumquantity is that which whenrevaporatedby the heat in the cuttings will cool the cuttings to the desiredtemperature.

. It is well-known that the B.t.u.s of heat required to evaporate wateris equal to the heat required to raise the water to 212 degrees F. plusthat required to evaporate the water. This can be expressed as follows:

Qw= w w w+ w w where Q =total quantity of heat; m =mass ofwater; L =theheat of vaporization of water; c =thermal capacity of water; and 't=temperature change of the water in rising to 212 degrees F. L =970B.t.u.s per pound and c,,, 1 B.t.u. per pound.

This formula, disregarding the efiect of the ambient air, gives thequantity of heat required to evaporate a certain mass of water.Accordingly, if the quantity of heat present in the cuttings is known,the amount of water which the cuttings are capable of evaporating can beresolved. 1

The .quantity of heat present in the cuttings is expressed by thefollowing formula:

In this formula Q =the quantity of heat present in the iron cuttings; m=mass of cuttings; c =the thermal capacity of the iron cuttings; and t=the drop in temperature of the cuttings.

Disregarding the very small effect which the ambient air has on thecooling of the cuttings, in the preferred form of the method of thisinvention the heat required to evaporate the water is equal to the heatlost by the cuttings. Thus, Q,,,=Q and m L +M c t =M c t Accordingly,

mlcc a uz w w Utilizing this formula and knowing the value of thefactors therein, the mass of the water can be determined. Itisthismassof water upon which the optimum amount to be mixed with the cuttingsis determined in accordance with the preferred form of this invention. Ahypo'thetical problem will illustrate the procedure for detel-miningthis amount of water.

-Suppose 100 lbs. of cuttings leave the burner and enter thernixer atIOOOdegrees F. andthe water mixed with the cuttings is at 60 degrees F.Also suppose the de- 4 sired resultant temperature of the cuttings isdegrees F. The thermal capacities of water (c and iron (c are l and .15,respectively. The heat of vaporization L for water is 970 B.t.u. perpound. Neglecting the effect of the ambient air, the formula would readas follows:

m =l2+lbs.

in accordance wtih this calculation, 12 pounds of water is added to each100 pounds of cuttings as they enter the mixer at 1000 degrees F.

Obviously, the ambient air has some efiect upon cooling the cuttings.The extent of such effect is very difficult to determine or predict.This cooling effect of the ambient air will decrease the amount of waterrequired to cool the cuttings by the evaporation thereof and accordinglythe quantity of water to be mixed with the cuttings may fall somewhatbelow the quantity as determined. by the above procedure. On the otherhand, other ambient conditions such as the humidity, temperature, etc.may have the opposite effect of requiring more water than thatdetermined by the above formula. Therefore, it should be understood thatin accordance with the preferred form of this invention, thepercentageof water to the Weight of cuttings may vary at least 25% moreor less than the amount determined by the above formula. The quantity ofwater added to the cuttings in the above hypothetical case would theirlie within the limits of 9 to 15 pounds of water per 100 pounds'ofcuttings.

This mixture of Water and cuttings has the consistency of mortar. Itwill stand alone but is still wet. Thus, the entire cuttings aresurrounded by particles of water and in the drying step the waterwithdraws the heat from the cuttings as it evaporates.

Although in the preferred form of this invention the amount of water tobe added to the cuttings is 25% more or less than the greatest amount ofwater that the cuttings will evaporate as determined 'by the aboveformula, I have found that less satisfactory results, but better resultsthan that obtained by previous type methods, is obtained by mixing withthe cuttings water in quantities outside this preferred range. It shouldbe understood, however,.that in all aspects of this invention thecuttings are cooled by some heat of evaporation. Water added to thecuttings in quantities greater than the preferred range must be lessthan the amount which by thermal capacity alone-will cool. the cuttingsto a temperature of 100 degreesF. This upper limit is easily determinedby the following formula:

Substituting the above hypothetical values for the factor in thisformula, m becomes equal to:

100 .15X (1000- 100) i 1x40 In this hypothetical case, 338 pounds ofwater will absorb the heat in the cuttings solely by its' thermalcapacity. Thus, it should be evident that a quantity less than 338pounds requires some cooling of the cuttings by heat of evaporation. 'e

The advantage of adding less than this amount of water is that lessadditional heat is required to dry the cuttings. The extreme case is thepreferred or optimum quantity of water wherein .the raising the water to212 degrees F. and evaporating it utilizes all of the excess heatcontent of the cuttings, thus requiring no additional heatto dry thecuttings. The exact amount of water within the broad range depends uponthe additional heat available at the operation site For example,- excessheat may be available for drying the cuttings, in which case it may beadvantageous to cool the cuttings more quickly by adding more water andthen drying the cuttings of that water which is not evaporated by theheat of the cuttings. The flue gases from the burner could probably beused for this purpose. In any event it should be realized thatsufiicient additional excess heat is practically never available forevaporating all the water mixed with the cuttings. The heat in thecuttings usually evaporates most of the water. As a result, rarely, ifever, is it feasible to mix with the cuttings a quantity of water whichwill almost entirely absorb the heat in the cuttings by its thermalcapacity alone. In cases, it is advisable to use water in quantitiesfalling within the optimum range of limits as previously described.

The cuttings ultimately produced by this invention are cooled to atemperature of 100 degrees F. At temperatures exceeding 100 degrees F.,the cuttings are subjected to oxidation which adversely influences theeffectiveness of the cuttings for use in the aniline reduction process.In some cases, the temperatures of the cuttings can be 200 degrees F.but preferably should not exceed that temperature.

The temperature of the water, of course, has a great effect upon theamount of water added to the cuttings. This temperature is taken intoaccount in the above formulas and thus the amount of water will changeaccordingly. The higher the temperature, the more water required and thelower the temperature the less water required.

The temperature of the cuttings also has an efiect upon the amount ofwater required. This effect is reflected in the above formulas andshould be evident therefrom. Considering the hypothetical case set upabove, in accordance with the broadest aspect of this in vention, watershould be added to 100 lbs. of cuttings in quantities less than 338pounds. In the preferred and narrow aspect of this invention, the amountof water added would lie in the range of 9 to pounds per 100 pounds ofcuttings. In such hypothetical case, this invention also covers allquantities of water from 9.0 to 338 pounds per 100 pounds of cuttings.

The cooling and drying step is very simple and can be accomplished byseveral means. The purpose of this step is to expose the cuttings to theambient air so that the water is permitted to evaporate therefrom. Thisis preferably accomplished without supplying any additional heat or highair currents. The cuttings are merely agitated to expose them to theair. My preferred amount of water added to the cuttings makes thispossible.

0n the other hand, it is conceivable that if an additional supply ofheat is available the water content can be increased and the additionalheat supply utilized for helping to evaporate the water from thecuttings. It is preferred, however, that the evaporation be accomplishedentirely by the cuttings rather than by any additional heat. It isbelieved that applying additional heat will result in greater oxidationof the cuttings thus adversely influencing the efiectiveness of thecuttings for use in.

the aniline reduction process. Using high air currents results in lossof fines which become entrained in such currents.

Apparatus Apparatus for performing the above operations is shown inFigs. 2, 3, 4 and 5. The burner 10, in this preferred apparatus, is acylindrical drum. This drum 11, is inclined at an angle. It is supportedby two cradles 12 and 13. The drum 11 has helical fins 61 extendingthroughout the entire length thereof for transferring cuttings insertedat one end to the other end. The drum is rotatably mounted on thecradles or pillars 12 and 13 by roller bearings mounted in bronzeliners. The

6 cradles as shown are constructed of concrete but any type of cradlecan be substituted therefore without departing from the scope of thisinvention.

The mechanism for rotating the cradle includes a gear ring 16 secured tothe outer circumference of the drum 11. The gear ring is fixed to thedrum and driven by a gear motor arrangement 17.

The top end 18 of drum 11 is open. The bottom. end 19 is closed by afunnel 20 (Fig. 3) secured to the cradle 13 by the straps 21. The funnel20 has an opening 22 at its bottom through which the cuttings pass, bymeans of chute 29, from the burner to the mixer. It also has an opening23 communicating with the waste fume stack 24. The funnel 20, waste fumestack 24, and chute 29 are held stationary by straps 21 while the drum11 rotates.

At the open end 18, a conveyor 25 is provided for carrying the cuttingsfrom a container 26 into the drum 11. A burner unit 27 extends into theend 18 to facilitate the burning or flashing of the oil as the cuttingspass through the burner.

The fume stack 24 leads to a separator or purifier 40, such as amulti-wash unit which is adapted to wash the waste gases removing anyharmful or odorous gases. The unit 40 is conventional, consisting of acylinder or stack 41, having a water inlet 42 and a waste outlet 43 atits top. The outlet 43 has a fan 44 therein which is sufiiciently largeto draw air through burner 10, stack 24, and cylinder 41. The fan inthis apparatus creates the draft through the burner 10, such draftproviding the excess air which is so essential in a preferred form ofthis invention as previously described. The fan 44 also disperses thewater throughout the cylinder 41 so that the water can work effectivelyin removing the undesirable gases.

An exhaust stack 45 communicates with the outlet 43 for carrying thefumes into the air streams normally occurring in the atmosphere.

The mixer 30 is constructed of a cylinder drum 31 freely rotatable onthe cradle 32 in substantially the same manner as the burner 10. Thedrum 31 extends into the dryer 50 and is concentric therewith. Mixer 30rotates on the roller bearings 33 which are in turn rotatably mounted inthe bronze liners 34 (Fig. 4). The cylinder 31 has helical fins 62 atits inner surface for transferring the mixture of cuttings and the waterfrom one end to the other. The receiving end of the cylinder .31 isclosed by the plate 35 which is held stationary in respect to thecylinder 31 by the straps 36 secured to the cradle 32. Plate 35 has anopening 40 for the water supply pipe 37 and an opening communicatingwith the chute 29 extending to the burner 10. The plate 35, supply pipe37, and chute 39 are all held stationary by straps 36 as the drum 31rotates. The drum 31 is driven by motor 410, gear 42, and gear ring 43(Figs. 2 and 4).

The dryer 50 is of substantially the same design as the mixer 30 andburner 10. It is a long, cylindrical, hollow member having helical fins63 on its inner surface for transferring the cuttings from one end tothe other. The cylinder 51 is supported by several cradlelike supports52 having the roller bearings 53 and bronze liners 54 (Fig. 5). Thecylinder 51 is driven by a mo tor 55 through the driving gear 56 and aring gear 57 secured rigidly and fixedly to the outer circumference ofthe cylinder 51. The cylinder 51 is open at both ends. The mixer 30extends into its receiving end so that the cuttings pass directly intodryer 50. The dispensing end is adapted to dispense the cuttings into acart 69 or any other type conveying means.

In the preferred form of this invention, no exterior heat is applied tothe dryer 50 and no high air currents are blown through the dryer. Thedrying is accomplished entirely by exposing the wet cuttings to theambient air, thus causing the water on the cuttings to evaporate andwithdraw heat from the cuttings. i

In its broadest. aspect, it may be desirable when more Water is usedthan that contemplated by my preferred form of this invention to passthe hot waste gases from the burner around the dryer, either in the formof a coil or a jacket surrounding the dryer. This additional heat wouldfacilitate the drying of the chips if the contents of the cuttings werenot suflicient to evaporate all the water. It should be understood thatsuch practice is only contemplated within the broadest aspect of thisinvention and that within the preferred aspects the evaporation of theWater on the cuttings is accomplished substantially entirely by the heatof evaporation.

The burner 10, mixer 30, and dryer 50, as illustrated are differentsizes. Burner 10 has a 42 inch diameter and 14 foot length. Good resultsare obtained by running it at 15 r.p.m.s which carries the cuttingsthrough the burner in 1 minute and l'sec'onds. The mixer 30 is 3 feetlong and 24 inches in diameter; It rotates at 60 r.p.m.s, thus carryingthe cuttings through it in 5 seconds. The dryer 50 is 30 feet longand 36inches in diameter. The cuttings are carried through it in 1 minute and17 seconds as it rotates at 26 r.p.m'.s.

It should be understood, that although specific sizes and speeds of allthese units have been given, that such sizes are not necessarilycritical. Various different sizes and speeds can be used depending uponvarious conditions, including the amount of water and oil in' cuttingsand the desired capacity. For example, the burner may be made longer ifrequiring a longer time to burn the oil from the cuttings. This, ofcourse depends upon the oil content of the cuttings and the temperatureofthe'burner. Increase or decrease in the size of the burner maynecessitate changing the size of the mixer and the dryer. The dryerssize may be changed in accordance with the time required to dry thecuttings, which depends entirely upon the water content of the cuttingsand water mixture.

Operation The operation of this apparatus is simple. First, the

motors for driving the burner, the mixture and the dryer 1 are set intooperation, thus, rotating the various units. Then the flame from theburner nozzle, the excess air, and the cuttings are all simultaneouslyfed into the burner at the receiving open end 18. As the cuttings areintroduced into the receiving end 18 of the burner 10, the heating flamefrom. the heater unit 27 is applied to raise the temperature of thechips. At the same time, excess air is drawn into the burner. Thisforrnsa strong draft through the drum and also provides excess oxygen forfacilitating a more complete combustion of the oil. I have found thatwith this apparatus, if more than 5 tons per hour of chips are passedthrough the drum and the oil content is high and the water contentlow,the heating flame is only necessary during the initial burning process.Thereafter, the oil on the chips furnishes enough fuel to sustain thetemperature for flashing or burning of the oil from the cuttings. Thisis especially made possible by the excess air.

As the chips pass through the drum 11, the heat in the dI'L'tIIl causesall the oil to vaporize and to ignite in the presence of the excess air.Thus, the oil burns to clear waste products such as carbon dioxide,carbon monoxide and water vapor. These fumes are drawn through the fumestack 24 and then passed through the unit 40. The water injected atinlet 42 is dispersed throughout cylinder 41 cleaning the fumes as theypass upwardly and the water spray falls downwardly. The gas is drawninto and blown out of the exhaust stack 45 by fan 44. i V

As stated previously, it is conceivable that these gases which are atrather high temperatures can be used for supplying excess heat to thedryer 50. In the preferred form of this invention, however, these wastegases are merely discarded. p p H V The cuttings; as they pass throughthe burner, are

, shipment.

transferred to the dispensing end 19 by the rotation of the drum 11 andthe helical fins 61. The fins 61, also agitate the chips thus exposingthe oil for evaporation and burning. The inclination of the burner 10also helps to transfer the cuttings from the receiving end to thedispensing end.

The cuttings 19, after all the oil has been burned off, pass through thechute 29 into the mixer 30. The cuttings at that time are at atemperature of approximately 800 to1200 degrees F. At this temperature,the cuttings are subject to oxidation, which is commonly referred to asrusting or corrosion. Thus, cooling such cuttings in the ambient airwould have a deleterious efiect upon the cuttings for use in the anilinereduction process. In accordance with this invention, the cuttings andthe water are introduced simultaneously into the receiving end of themixer 30. Water can be sprayed either at such entrance or at theintermediate part, depending upon the various circumstances. Thepercentage by weight of water to cuttings is that previously discussed.In the preferred form of this invention, such ratio is calculated inaccordance with the formula mtvc c m c t mwcwiw The water mixed with thecuttings results in a mixture which has the consistency of mortar.During the mixing step, inherently some of the water is evaporated,resulting in the lowering of the temperature of the cuttings. Also thecuttings temperature is lowered due to the thermal capacity of the waterwhich rises to 212 degrees F. before evaporating. This entire mixingprocess takes about 5 seconds.

The mixture or slurry of cuttings and water passes into the dryer 50.The dryer 50 transfers the cuttings from the receiving end to thedispensing end. During such transfer the drum 51 constantly rotates andagitates the cuttings, exposing them to the ambient air. The chips orcuttings dry by evaporating the water thereon. The entire drying processtakes about 1 minute, 17 seconds. I

At the exit or dispensing end of the drum 51, a cart 60 or otherconveyance means is located for catching the cuttings which are thentransferred to loading spot for packing into boxes or other containersready for In operating the above described apparatus, the water requiredto cool a definite amount of cuttings to degrees F. was measured. It wasdetermined that 172 pounds of water was required to cool 2000 pounds ofcuttings whose temperature at the exit of burner 10 varied from 880-1020degrees P. (930.45 degrees F. average). The temperature of the watermixed with the cuttings was 40 degrees F. and the ambient temperature 22degrees F.

In accordance with the above formula the following quantity of water isrequired:

m c t uz at...

218 lbs. of water 9 It should be evident that the exact amount of waterrequired in practice is 21% less than that theoretically required. Thisdifference is explainable because of the cooling efiected by the 22degrees F. ambient air and other conditions. The practical amountrequired does,

however, fall within the broad and narrow limits of this invention.

With this apparatus, I have found that I can more than triple the outputof conventional methods for cleaning cuttings. My apparatus is also muchless expensive to run and less complicated than other type apparatusesin which the cuttings are cooled by a cooler jacket.

With my apparatus, the loss due to oxidation and loss of fines is alsogreatly reduced. In older methods, 12% and above losses are very commonwhile in my apparatus lo'ss is reduced to below 8%. This is due probablyto the reduction in oxidation and also due to the reduction in loss offines resulting from high velocity air currents being injected throughthe cooling chambers. Usually the velocity of such air currents exceedsthe entraining velocity of the bulk of the fines, thus the currentscarry the fines out of the cooling chamber, resulting in the loss ofsuch fines. In my apparatus, I do not pass a high velocity air currentthrough the drying chamber. The entire drying process is accomplishedwith the normal air running through such chamber. This is made possibleby cooling the cuttings by the heat of vaporization of the water ratherthan having the air itself dry and cool the cuttings.

My invention also is more economical because after it is started, itdoes not require any additional fuel or flame for sustaining theprocess. Above 5 tons per hour, the oil content of the normal cuttingspassing through the burner is sufiicient to fire the process, thuseliminating the need for any additional fuel such as oil or gas.

My invention under the right conditions is thus a selffiring exothermalprocess rather than an endothermic process. This is made possible due tothe capacity of the unit which can handle 5 tons per hour of cuttings ofhigh oil content and also due to the forcing of excess air through theburner, resulting in more complete combustion. In conventional burners,passing more than 5 tons per hour through them would be very hazardousbecause of the explosion possibilities.

It should be evident that my invention, both as to the method andapparatus, is entirely new and has many advantages over other methodsand apparatuses for cleaning. cuttings. It should be understood thatalthough I have described preferred method and apparatus for obtainingthese new results, other equivalent structures and methods can be usedwithout departing from the scope of this invention. Therefore, all suchequivalent forms -will be considered within the scope of this inventionunlessexpressly excluded by the appended claims.

I claim:

1. Apparatus for cleaning oily metallic cuttings comprising a. burnermeans having a combustion chamber with an inlet at one end and an outletat the other; means for transferring said cuttings from the inlet to theoutlet; meanscausing combustion of the oil on the oily cuttings forburningsaid oil off said cuttings as they'pass from said inlet to saidoutlet; a mixer having an inlet adapted to receive said cuttings afterthey pass out of said burner means outlet; a water source communicatingwith said mixer; means for regulating the amount of water per unit timeflowing into said mixer; said mixer having means for mixing saidcuttings with said water to form a slurry and transferring said slurryto a mixer outlet; a dryer having an inlet adapted to receive saidslurry after it passes out of said mixer outlet; said dryer having meansfor exposing the particles of said slurry to the ambient air wherebysaid water on said cuttings evaporates and by the heat of vaporizationrequired by such evaporation cools said cuttings.

2. Apparatus for cleaning oily metallic cuttings comprising a burnerhaving an inlet at one end and an outlet at the other; means fortransferring said cuttings from the inlet to the outlet; means forsupplying excess oxygen to said burner in greater quantities thannormally occurring in the ambient air; means for supplying combustiblefuel to said burner whereby when ignited said oil is burned off saidcuttings with the help of said fuel and excess oxygen; a mixer having aninlet adapted to receive said cuttings after they pass out of saidburner outlet; a water source communicating with said mixer; means forregulating the amount of water per unit time flowing into said mixer;said mixer having means for mixing said cuttings with said water andtransferring said mixture to a mixer outlet; a dryer having an inletadapted to receive said cuttings after they pass out of said mixeroutlet; said dryer having means for exposing the particles of saidmixture to the ambient air whereby said water on said cuttingsevaporates and by the heat of vaporization required by such evaporationcools said cuttings.

3. Apparatus for cleaning oily metallic cuttings comprising a hollowcylindrical burner housing having a combustion chamber with an inlet atone end and an outlet at the other; rotatable helical means fortransferring said cuttings from said inlet to said outlet; means causingcombustion of the oil on the oily cuttings for burning said oil on saidcuttings as they pass from said inlet to said outlet; a mixer having aninlet adapted to receive said cuttings after they pass out of saidburner housing outlet; a water source communicating with said mixer;means for regulating the amount of water per unit time flowing into saidmixer; said mixer having means for mixing said cuttings with said waterto form a slurry and transferring said slurry to a mixer outlet; a dryerhaving an inlet adapted to receive said slurry after passing out of saidmixer outlet; said dryer having means for exposing the particles of saidslurry to the ambient air whereby said water on said cuttings evaporatesand by the heat of vaporization required by such evaporation cools saidcuttings.

4. Apparatus for cleaning oily metallic cuttings comprising a burnerhousing having a combustion chamber with an inlet at one end and anoutlet at the other; means for transferring said cuttings from the inletto the outlet; means causing combustion of the oil on the oily cuttingsfor burning said oil off said cuttings as they pass from said inlet tosaid outlet; a hollow cylindrical mixer having an inlet adapted toreceive said cuttings after they pass out of said burner outlet; a watersource communicating with said hollow cylindrical mixer; means forregulating the amount of water per unit time flowing into said hollowcylindrical mixer; said mixer having rotatable helical means for mixingsaid cuttings with said water to form a slurry and transferring saidslurry to a mixer outlet; a dryer having an inlet adapted to receivesaid slurry after it passes out of said mixer outlet; said dryer havingmeans for exposing the particles of said slurry to the ambient airwhereby said water on said cuttings evaporates and by the heat ofvaporization required by such evaporation cools said cuttings.

5. Apparatus for cleaning oily metallic cuttings comprising aburnerhousing having a combustion chamber with an inlet at one end and anoutlet at the other; means for transferring said cuttings from the inletto the outlet; means causing combustion of the oil on the oily cuttingsfor burning said oil ofi said cuttings as they pass from said inlet tosaid outlet; a mixer having an inlet adapted to receive said cuttingsafter they pass out of said burner housing outlet; a water sourcecommunicating with said mixer; means for regulating the amount of waterper unit time flowing into said mixer; said mixer having means formixing said cuttings with said water to form a slurry and transferringsaid slurry to a mixer outlet; a hollow cylindrical dryer having aninlet at one end adapted to receive said slurry from said mixer; saiddryer having rotatable helical means for exposing the particles of said1'1 slurry to the ambient air and transferring saidmixture to the otherend. i

6. Apparatus for cleaning oily metallic cuttings comprising a burnerhaving an inlet at one end and an outlet at the other; means fortransferring said cuttings from the inlet to the outlet; means forburning said oil oif said cuttings as they pass from said inlet to saidoutlet; means for supplying excess air to said burnerin greaterquantities than normally occurring in the burner; means of supplyingcombustible fuel to said burner whereby when ignited said oil is burnedoff said cuttings with the help of said fuel and excess oxygen; a hollowcylindrical mixer having an inlet adapted to receive said cuttings afterthey pass out of said burner outlet; a water source communicating withsaid hollow cylindrical mixer; means for regulating the amount of waterper unit time flowing into said hollow cylindrical mixer; a dryer havingan inlet adapter to receive said cuttings after they pass out of saidmixer outlet; said dryer having means for exposing the particles of saidmixture to the ambient air whereby said water on said cuttingsevaporates and by the heat of vaporization required by such evaporationcools said cuttings.

7. Apparatus for cleaning oily metallic cuttings comprising a burnerhaving an inlet at one end and an outlet at the other; means fortransferring said cuttings from the inlet to the outlet; means forburning said oil ofi said cuttings as they pass from said inlet to saidoutlet; means for supplying excess air to said burner in greaterquantities than normally occurring in the burner; means for supplyingcombustible fuel to said burner whereby when ignited said oil is burnedoff said cuttings with the help of said fuel and excess oxygen; a mixerhaving an inlet adapted to receive said cuttings after they pass out ofsaid burner outlet; a Water source communicating with said mixer; meansfor regulating the amount of water per unit time flowing into saidmixer; said mixer having means for mixing said cuttings with said waterand transferring said mixture to a mixer outlet; a hollow cylindricaldryer having an inlet at one end adapted to receive said cuttings fromsaid mixer; said dryer having rotatable helical means for exposing theparticles of said mixture to the ambient air and transferring saidmixture to the other end.

8. Apparatus for cleaning oily metallic cuttings comprising a hollowcylindrical burner having an inlet at one end and an outlet at theother; rotatable helical means for transferring said cuttings from saidinlet to said outlet; means for supplying excess oxygen to said burnerin greater quantities than normally occurring in the ambient air; meansfor supplying combustible fuel to said burner whereby when ignited saidoil is burned off said cuttings with the help of said fuel and excessoxygen; a mixer having an inlet adapted to receive said cuttings afterthey pass out of said burner outlet; a water source communicating withsaid mixer; means for regulating the amount of water per unittimeflowing into said mixer; said mixer having means for mixing saidcuttings with said water and transferring said mixture to a mixeroutlet; a dryer having an inlet adapter to receive said cuttings afterthey pass out of said mixer outlet; said dryer having means for exposingthe particles of said mixture to the ambient air whereby said water onsaid cuttings evap- 12 orates and by the heat of vaporization requiredby such evaporation cools said cuttings.

9. Apparatus for cleaning oily metallic cuttings comprising: burnermeans having a combustion chamber; a mixer; and a drier; means in saidburner means causing combustion of the oil on the oily cuttings forburning said oil 01f said cuttings while passing through said combustionchamber; means for transferring said cuttings from said burner to saidmixer; a water source communicating with said mixer; means forregulating the amount of water per unit time flowing into said mixer;said mixer having means for mixing said cuttings with said water to forma slurry; means for transferring said slurry from said mixer to saiddrier; said drier having means for exposing the particles of said slurryto the ambient air whereby said water in said slurry evaporates and bythe heat of vaporization required by said evaporation cools saidcuttings.

10. Apparatus for cleaning o'ily metallic cuttings comprising; burnermeans; a mixer; and a drier;.means in said burner means for burning saidoil ofi said cuttings; means for supplying excess air to said burner ingreater quantities than normally occurring in the burner; means fortransferring said cuttings from said burner to said mixer; a watersource communicating with said mixer; means for regulating the amount ofWater per unit time flowing into said mixer; said mixer having means formixing said cuttings with said water to form a slurry; means fortransferring said slurry from said mixer to said drier; said drierhaving means for exposing the particles of. said slurry to the ambientair whereby said water in said slurry evaporates and by the heat ofvaporization required by said evaporation cools said cuttings.

11. Apparatus for cleaning oily metallic cuttings comprising anelongated burner housing having an inlet end and an outlet end; means insaid burner for conveying cuttings from said inlet end to said outletend; means at said inlet end for starting combustion of the oil on saidcuttings; and blower means for causing sufficient quantities of excessair to pass through said elongated housing from said inlet end to saidoutlet end for supporting the combustion of said oil from said inlet tosaid outlet ends.

References Cited in the file of this patent UNITED STATES PATENTS620,355 Potter Feb. 28, 1899 935,477 Evans Sept. 28, 1909 1,207,512Dickson Dec. 5, 1916 1,231,002 Dawson June 26, 1917 1,383,418 NeedhamJuly 5, 1921 1,580,723 Hapgo'od Apr. 13, 1926 1,901,803 Davis Mar. 14,1933 1,912,810 Wechter June 6, 1933 2,288,980 Turin July 7, 19422,478,461 Connolly Aug. 9, 1949 2,538,057 Steele Jan. 16, 1951 2,673,081Fay Mar. 23, 1954 2,717,845 Carter Sept. 15, 1955 FOREIGN PATENTS128,065 Australia July 8, 1948

